Summary cells of newborn infants (6).In order to define the normal range of selenium levels and to'e;aluate whether any correlation exi& Paired and plasma and in the human between selenium and GSH-Per activity, paired as well as samples from nonpregnant adult females, were assayed samples of maternal and cord erythrocytes and plasma, respecfor selenium and for glutathione peroxidase (GSH-Per) activity. tively, were assayed for selenium and for GSH-Per activity. Fetal selenium levels, both in red cells (0.39 f 0.08 pg/ml) and in plasma (0.13 f 0.03 pg/ml), were significantly lower than the respective levels in either pregnant ( P C 0.001) or nonpregnant ( P MATERIALS AND METHODS < 0.001) female adults. GSH-Per activity in fetal red cells (576 f 131 U/100 ml) and plasma (10.3 + 4.0 U/100 ml) were similarly Paired samples of maternal and cord blood were obtained, with significantly lower than the respective levels of activity in each maternal consent, at the time of delivery after full term gestation.group of adult samples ( p < 0.001). Erythrocyte selenium levels Blood samples were also taken from healthy house officers, nurses, were similar in nonpregnant (0.~2 0.05 pg,ml) and pregnant and laboratory technicians of both sexes. The blood specimens (0.52 f 0.07 p g / d ) adult females; but there was a significant were into he~arinized which had difference in erythrocyte GSH-Per activity between the nonpreg-been checked previously to ensure the absence any trace nant (832 2 165 U/100 ml) and the pregnant (990 + 207 U/100 amounts of in the ml) groups (0.02 < P < 0.03). The plasma levels of selenium in the Red were separated by centrifugation at 2500 vm nonpregnant females (0.21 + 0.03 pg/ml) were significantly higher in a Sowall RC5 refrigerated centrifuge at 20, and the plasma was than in the pregnant group (0.19 + 0.03 &ml) (0.01 < P < 0.02); removed and frozen for subsequent assay cf and of similarly, plasma enzyme activity in the nonpregnant group (19.5 GSH-PerThe buff^ 'Oat was and discarded, + 4.4 U/lOO was significantly higher than in the pregnant and the red cells were washed three times in cold isotonic saline group (14.0 3.2 U/lOO ml) (P < O.OO1). A close positive and then resuspended to an hematocrit of approximately 40%. A correlation was found between selenium levels and GSH-Per portion of the red cell suspension was removed for microhematoactivity, both in plasma and in red cells ( r = 0.86).mothers, crit and hemoglobin determinations, and 0.20-ml aliquots were values for enzyme activity and for selenium, both in plasma and in frozen for later determination of 'Ontent. erythrocytes, were almost invariably higher than the comparableThe glutathione peroxidase of the red was values in her own fetus.in either fresh saline suspensions, or in samples frozen for not more than 24 hr, using Whaun and Oski's modification (20) of the method of Paglia and Valentine (12). Enzyme activity was meaSpeculation sured at 2S0 in a Zeiss PM 6 spectrophotometer and was expressed Selenium has a biologic role as a component...

Thyroid lobectomy is an effective surgical strategy to manage papillary microcarcinomas with low complications. Routine completion thyroidectomy is not mandatory. Appropriate selection excluding high-risk patients is of paramount importance in order to achieve the best results.

The deleterious effects on erythrocytes of low steady-state concentrations of H2O2 in vitro have been compared in samples from full-term and premature infants and adults. Methemoglobin and Heinz bodies were formed to a greater degree in the intact erythrocytes of the young subjects. In the absence of protective enzymes, however, the extent of oxidation was similar in hemoglobin prepared from cord blood and from adult blood, respectively. Activity of the enzymes involved in the detoxification of H2O2 has been measured in the red blood cells of the aforementioned groups of subjects. Of note was the finding of significantly decreased activity of glutathione peroxidase in the full-term newborn and premature infants. These findings of increased toxicity from H2O2 and decreased efficiency of the detoxification mechanisms are considered to have bearing on the susceptibility of young subjects to drug-induced hemolytic anemia.

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ABSTRACT. To obtain a profile of erythrocyte antioxidant defense potential during late fetal development, we studied selected antioxidant parameters in blood samples from 65 neonates with birth wt between 520 and 4210 g and from 12 healthy adults. Erythrocyte superoxide dismutase activity did not change significantly with maturation and no significant differences were observed among preterm infants grouped in increasing birth wt categories, term neonates, and adults. Erythrocyte catalase and glutathione peroxidase, as well as plasma vitamin E levels, showed highly significant positive correlations ( p < 0.001) with increasing fetal wt and gestational age; by term, CAT activity reached a level similar to the adult control group, but glutathione peroxidase activity, as well as plasma vitamin E levels, were markedly lower in all the preterm and in the term groups than in adults ( p < 0.01). Erythrocyte glutathione S-transferase activity showed a negative correlation with increasing gestational age ( p < 0.01) and the adult values were considerably lower than any of the neonatal levels ( p < 0.001). The role of glutathione Stransferase in erythrocyte metabolism remains obscure. Maturational changes in the activity of the red cell enzymes that were studied and in the plasma vitamin E level were apparent from about 31-36 wk of gestation, suggesting that the stimulation for these changes may have commenced from about 28-31 wk. (Pediatr Res 26: 366-369, 1989) Abbreviations CAT, catalase SOD, superoxide dismutase GSH-Px glutathione peroxidase GSH-Px[H202], glutathione peroxidase with hydrogen peroxide as substrate GSH-Px[t-bh], glutathione peroxidase with t-butyl hydroperoxide as substrate GST, glutathione S-transferase The evolution of oxidative metabolic processes within mammalian cells has necessitated the concomitant development of mechanisms to protect vital cell components against oxygeninduced damage that could result from oxygen free-radical species produced during metabolism. These antioxidant systems include both enzymatic and nonenzymatic mechanisms. Vitamin E appears to be the most significant non-enzymatic antioxidant, and CAT, SOD, and selenium-dependent GSH-Px are believed to be the primary enzymatic systems; however, a role